The following disclosure relates generally to methods and systems for analyzing complex machinery and, more particularly, to computer-based methods and systems for performing integrated analyses of gas turbine and combined cycle power plants.
Many power plants employ turbines, such as steam or gas turbines, for the generation of electrical power. A typical gas turbine system includes at least an air inlet, a compressor, a combustor, and a turbine. The air inlet directs air into the compressor, which increases the air pressure. From the compressor, the pressurized air passes to the combustor, where the ignition of fuel introduced into the air stream heats the air and further increases the air pressure. From the combustor, the high pressure air flows into the turbine, which converts the kinetic energy of the air into mechanical shaft energy. This shaft energy is typically provided to a generator for generating electrical power. In addition, in some gas turbine power plants, a heat exchanger is positioned in the low pressure exhaust flow exiting the turbine to generate steam, which passes through a separate steam turbine to generate additional electrical power.
A typical turbine includes an alternating series of fixed stator blades or xe2x80x9cnozzlesxe2x80x9d and rotatable rotor blades or xe2x80x9cbuckets.xe2x80x9d Throughout this disclosure, the term xe2x80x9cexpanderxe2x80x9d will be used instead of the word xe2x80x9cturbinexe2x80x9d when referring to the actual turbine portion of a gas turbine system (i.e., the nozzle and bucket assembly), to avoid confusion with the word xe2x80x9cgas turbine,xe2x80x9d which will be used when referring to the overall gas turbine system that includes at least the compressor, combustor, and expander.
Important performance characteristics for power plants employing turbines can include power output, fuel usage rate, component operating life, exhaust gas temperature and composition, heat recovery system power output, and costs. As is known by those of ordinary skill in the relevant art, there are numerous engineering and economic analyses that can be used to evaluate these characteristics. For example, an aerodynamic analysis that focuses on the gas flow around the expander nozzles and buckets can be used to estimate power output from the expander. Similarly, a thermal analysis of the expander components in the hot gas path can be used to estimate component operating temperatures. These operating temperatures can then be used in conjunction with component stress analyses to estimate operational lifetimes for these components. Other known gas turbine analyses that can be used to evaluate the performance characteristics listed above include secondary flow analysis, heat recovery analysis, heat balance analysis, equipment and installation cost analysis, and operation and maintenance cost analysis.
Traditionally, each different type of gas turbine analysis has involved the use of a separate computer program, the execution of each program being the responsibility of a separate analytical group trained in that particular area of analysis. Although the different analyses are performed by separate groups, the results from the different analyses are typically integrated, at least at some level, by using the results from one program as variables or boundary conditions for one or more of the other programs. For example, the results from a hot gas path heat transfer analysis may be used as boundary conditions for the operating life analysis for a particular component.
In addition to integrating the results from the different analyses, the results are often compared to ensure they are physically consistent, and hence credible. For example, the gross power output resulting from the aerodynamic analysis of the expander can be compared to the net power output resulting from the overall gas turbine performance analysis to ensure that the net power output from the gas turbine does not exceed the gross power output from the expander. If such a comparison of results exposes an inconsistency between the different analyses, then the analyses are typically iterated after adjusting the variables to try and converge the analyses toward consistent solutions.
Conventional methods for integrating analyses and comparing results as described above typically involve the manual exchange of information between different analytical groups. This manual exchange can be both time-consuming and error-prone, especially when numerous iterations of the different analyses are required to converge the solutions. Accordingly, methods and systems that reduce the time and effort required by conventional systems to analyze gas turbine power plant configurations are desirable.